Cluster bombs have a bad rep and for good reasons. Yet, the cluster bomb concept has evolved from the dumbest of dumb bombs into a more targeted and discriminating weapon. One of these new cluster munitions in particular is incredibly complicated, heinously smart and ridiculously effective. They call it the Sensor Fuzed Weapon.
Traditionally, cluster bombs have been indiscriminate, wide area killers, both in their initial attack and via unexploded submunitions, often called 'bomblets,' that can look like brightly colored bouncy-balls or soda cans. This has led to the maiming and death of many innocent civilians and especially curious children around the globe. The delivery system for traditional cluster bombs have also lead to unintended effects of the battlefield. Until about a decade ago, cluster munitions relied strictly on 'gravity bombing' techniques that can be effected by wind and the stump-like aerodynamics of cluster munitions dispensers. Since combat aircraft often fly high to avoid anti-aircraft fire, traditional bombing runs would result in cluster weapon going wildly off course. This, paired with the large area these munitions effect have led to horrible, although unintended loss of innocent lives.
The Sensor Fuzed Weapon and other emerging 'smart' cluster bomb technologies aim to fix these deficiencies while also delivering an even heavier and more targeted punch to the enemy.
Without seeing it work in slow motion, you would think the concept behind the CBU-97 Sensor Fuzed Weapon, and the BLU-108 Sensor Fuzed submunitions it deploys, seems unrealistic, bordering on silly. Yet the truth is that this intricate weapons concept works incredibly well and has proven itself in combat to a stunning degree.
The idea behind the Sensor Fuzed Weapon goes something like this: Pack a handful of BLU-108 submunition 'cylinders' into a single 'delivery system.' In this case, let's limit the description it to the CBU-97 Sensor Fuzed Weapon housing, although cruise missiles and even artillery rockets can deliver the BLU-108 submunitions as well. The CBU-97 is very similar to the 'peel away,' drum-like cluster bomb canisters of decades past. Once dropped over an enemy formation, surface-to-air missile site or air base, the cluster bomb 'canister' will peel open at a predetermined height and out will pop ten BLU-108 submunition cylinders.
Once these 64 pound, 31 inch long submunitions are released, each will deploy a parachute, slowing their forward movement and orientating them vertically in relation to the ground. Then, a rocket motor fires and forces these cylinders into a slight climb, although at a distance it would look like the BLU-108s are hanging in mid-air. This rocket also causes the BLU-108s to spin rapidly.
As the submunition spins while almost hovering in mid-air above the target area, each BLU-108 cylinder will throw four individual sub-submuntions, known as 'Skeets,' from its body. Each Skeet is slung in a different direction at a 90 degree vector from the now empty BLU-108 cylinder. As these hockey puck-like Skeets fly through the air while rapidly spinning, a small infrared imager and laser ranging system activates on each one. The infrared seeker rapidly scans the ground below for an enemy vehicle or weapons fixture that it can recognize, while the laser ranger provides a ground contour map.
Trucks, armored personnel carriers and main battle tanks are not the only targets the BLU-108's Skeets can recognize and engage. Surface-to-air missile launchers, radars and even parked aircraft and support equipment can also be recognized and prioritized, giving the system a destruction of enemy air defenses (DEAD) and airfield attack capability as well as an anti-armor role.
Ok, so I know you reading this and asking yourself: "are you telling me these little flying pucks can recognize bad guys' vehicles and automatically decide whether or not to engage them while they spin freely through the air at high RPM?" The answer is unequivocally YES.
The Skeet's dual mode laser and infrared seeker compares imagery and dimensional information of what they 'see' with data stored in their memory banks. They can then rapidly classify what is a target and what is not. Since each Skeet was slung in a different direction upon deployment from the spinning BLU-108 submunition, there is little chance that more than one Skeet targets the same vehicle, aircraft or weapons fixture during the attack.
Once a target is selected, the Skeet fires off its 2lb explosively formed penetrator along with a fragmentation ring, sending a molten spear into the target along with a handful of dense shrapnel covering the area around it. The idea is that the penetrator kills the vehicle from top, where even main battle tanks are vulnerable, while the shrapnel kills who is inside (if it is a lightly armored target) and anyone in the targeted vehicle's immediate vicinity. If a target is not identified by the Skeet to engage, the Skeet will self destruct while still high above the ground. If this fails, a backup timer disables the Skeet after landing on the ground.
Once the Skeet is made inert, it is extremely resistant to exploding via tampering. This self-inert capability takes away some of the biggest arguments against cluster munitions: the fact that unexploded submunitions can harm bystanders a long time after an attack was originally executed. The result of which has left many men, women and especially children, limbless or worse.
Although the BLU-108 can be integrated into many delivery systems, the main one used is the aforementioned 'unguided' CBU-97 Sensor Fuzed Weapon. Like the ten BLU-108 submunitions housed within it, it is built by Textron Defense Systems. Those ten BLU-108s give the CBU-97 a total of 40 Skeets to dispense. These 40 Skeets can cover an area measuring up to 1500 feet by 500 feet. that is approximately 15 acres! Alternatively, the system can be programmed to open at much lower altitudes, which would apply its devastating effects to smaller, more target rich areas. The flexibility the CBU-97 offers makes employing it more of an artform than a science.
Although the BLU-108 and its CBU-97 delivery system were originally designed with low-flying tactical aircraft in mind, the weapon system can be fielded in mass aboard America's heavy bomber fleet. A single B-52H Stratofortress loaded with CBU-97s has the ability to take out an entire armored division. Before the CBU-97's development, such a feat would have taken many attack aircraft, big or small, and many hundreds of individual precision guided munitions, or possibly thousands of cluster bombs and dumb bombs to achieve.
Clearly, the BLU-108 and CBU-97 Sensor Fuzed Weapon pair represent a giant leap forward in precision air-to-ground weaponry, if not by the pair's volume of precision fire alone, than by the system's miniaturized autonomous targeting capabilities. Yet the CBU-97 and BLU-108 combo still have one massive drawback, for all the smart bomblets, or 'Skeets' it contains, the basic delivery system still remains 'dumb.' In other words, an aircraft still has to deliver the CBU-97 Sensor Fused Weapon dispenser using close-in, unguided gravity bombing techniques. In doing so, atmospheric conditions and human error can send the CBU-97 off course, to an area where no targets exist for it to engage at all. This is especially true considering combat aircraft crews would often have to deliver the CBU-97 from medium or even high-altitude to avoid enemy ground fire, and often times the target area would be formations of vehicles strung out linearly on a narrow roadway or ridge far below. A little to the left or to the right and the CBU-97's precious Skeets may end up frantically searching a field full of goats for possible targets. This is where the 'guided' Wind Corrected Munitions Dispenser (WCMD) kit comes in to play.
The WCMD adds an 'intelligent' tail section that contains maneuvering fins and an inertial navigation system to existing cluster bombs. Each tail-kit costs around $10k, a bargain when it comes to guided munitions. Part of the reason why the WCMD is relatively affordable is that although it is still considered a precision guided munition, a cluster bomb, by its very nature, doesn't have to be that precise. It simply has to deploy its deadly payload within a circular error of probability of dozens of yards (or about 85 feet officially), whereas the Joint Direct Attack Munition, which is a similar concept, existing as a tail attachment for 'dumb' high-explosive bombs, has a circular error of probability of about a dozen feet or less. In some cases laser guided munitions have an even a lower CEP than that.